The Monroe County Sheriff's Office worked with mainland law enforcement to quickly make arrests and find a powerful military assault rifle and other guns stolen last week in a series of Upper Keys home burglaries.

The case involves two home burglaries and a stolen pickup truck that was found burning in Florida City. That arson case remains under investigation by Florida City police, said sheriff's office spokeswoman Becky Herrin.

Sheriff Rick Ramsay feared the stolen guns and an upset suspect could have led to a standoff or a fire fight, he said.

"This had a lot of potential to be bad, because the guy was not stable and talking about a potential shootout with law enforcement," Ramsay said. "I put probably 15 to 18 officers on nothing but this. I'm talking special operations detectives, intelligence detectives, lieutenants -- everyone. This was job one, and the focus was on this and this only until we got these guns back and arrests made. We had three crime scenes in two counties and multiple suspects. It happened fast, but we responded."

Those arrested as of Tuesday are:

• Matthew Joseph Berry, 23, of Tavernier, remains in custody in Miami-Dade County with an arrest warrant out of Monroe County on charges of armed burglary, grand theft and dealing in stolen property.

Officers were worried about Berry early into the case because he told detectives on the phone that he was upset over his pregnant girlfriend's suicide and was abusing drugs and alcohol, Ramsay said.

• David Lee Gilliland, 26, of Tavernier, was charged with fleeing and eluding police, driving with a suspended driver's license with knowledge and possession of cocaine. He will likely also be charged with possession of firearms by a convicted felon, Herrin added.

• David Justin Pothier, 25, of Plantation Key, was charged with being a principle to armed burglary, grand theft and dealing in stolen property.

Herrin and detectives gave the following account of how the case transpired:

It began with Upper Keys detectives investigating a March 26 burglary on Meridian Avenue in Key Largo, where the homeowner reported his AR-15 military assault rifle, a Glock handgun and pellet gun had been stolen from his home, as well as a Ford F-150 pickup.

The owner had been out-of-town and left his house unlocked, reports state. Berry had previously met the owner and stole the items after learning the owner would be gone, Herrin said.

Detectives would later learn that the stolen Ford F-150 was found by Florida City police destroyed by fire, Herrin said.

While detectives were investigating the Meridian Avenue burglary, they were called to Azalea Street in Tavernier, where the resident there reported a shotgun and laptop computer stolen.

That owner also said two men he knows, Berry and Pothier, had attempted to sell him an AR-15, a Glock and a pellet gun the previous day, but he declined, reports state. The next day (March 26), he realized someone had broke into his home sometime between when Berry and Pothier were there and when the owner left, Herrin said.

Detectives identified Berry as a suspect, and spoke to him on the phone several times in the hopes he would return the guns safely. He reportedly refused to cooperate, and deputies issued a be-on-the-lookout (BOLO) for him as well as his Chevrolet 2500 pickup.

Berry was found March 27 in Homestead, where he was taken into custody by Homestead police without incident, Herrin said.

Detectives say Berry identified Pothier and Gilliland as accomplices.

Also on March 27, Gilliland was observed by a sheriff's office surveillance team driving a white Mustang at Mile Marker 89 about 2:30 p.m., which led to a brief chase then a foot chase before he was apprehended, reports state.

He told detectives the guns were at a friend's home in Islamorada. That person has not been charged, Herrin said.

Pothier was located at Seabreeze R.V. and Mobile Home Park, 87425 Old Highway in Islamorada, where he was arrested without incident, reports state.

A citizen's tip led detectives to Pothier, who was cooperative with detectives, Herrin said.

"We work well with Homestead, Florida City and our partners in Miami-Dade as criminals go back and forth between here and there," Ramsay said. "These guns were not only a threat to us, but a threat to residents there as well."